Methods: We have conducted an open observational study of the use of spironolactone 25-50 mg in the management of patients with resistant hypertension. This drug was recommended in 133 patients who were already receiving an angiotensin-blocking drug in addition to other therapies.
Results: Of these, three defaulted from follow-up and 11 could not tolerate spironolactone. We therefore have outcome data on 119 patients. The addition of spironolactone (median dose 25 mg) was associated with a mean (SD) fall in systolic blood pressure of 21.7 mmHg (24.0; P < 0.001) and diastolic blood pressure of 8.5 mmHg (14.9; P < 0.001). In two patients spironolactone had to be discontinued on account of a rise of serum potassium to above 6.0 mmol/l, whereas overall the mean increase in serum potassium was 0.3 mmol/l.
Conclusion: With careful monitoring of plasma electrolytes, spironolactone at a low dose is an effective add-in drug in patients with hypertension resistant to a regime that includes an angiotensin-blocking agent.